Study highlights how population density and location shape litter levels facing UK communities

A network of citizen scientists were asked to carry out monthly litter picks at set locations over the space of five months
Plastic bottle and other plastic marine litter on a beach
Almost 60% more litter can be found in the UK’s coastal communities than in inland locations, according to new research.
A study, published in the journal Marine Pollution Bulletin, is the first UK-based research to investigate the effects of population density and community on the accumulation of litter in the environment.
It recruited a network of citizen scientists, comprising 97 volunteers based everywhere from the coasts of Cornwall, Cumbria and Kent to urban locations including London, Leeds and Leicester.
They were asked to carry out monthly litter picks at set locations over the space of five months, cataloguing the quantities and types of litter they found using a smartphone application.
This allowed researchers to observe trends in the litter’s accumulation and abundance, while also enabling them to explore any connections between quantities of litter and population density.
Overall, between May and September 2021, the volunteers collected just under 28,000 items including more than 9,200 pieces of hard plastic and other fragments, 9,150 items of food wrappers and other packaging, and 6,300 pieces of cigarette-related debris, including butts and lighters.
The litter density was almost 60% higher in coastal areas compared to inland regions (0.053 items per m² compared to 0.03 items m²), with urban areas consistently exhibiting more litter than rural areas in both coastal and inland locations.
However, over the course of the five-month study, coastal areas experienced a significant influx of new litter whereas levels in inland regions were either stable or decreasing.
Writing in the study, the researchers say this could be down to a combination of litter being transported to the coast from inland via rivers and storm overflows, as well as more items being dropped by holidaymakers during the summer months.
Also, while there was no significant difference in levels of litter in coastal urban and coastal rural communities, but inland urban areas had significantly more litter than their rural counterparts.
The study was carried out by scientists from the International Marine Litter Research Unit at the University of Plymouth, ZSL, Nantes Université, and the campaign group Surfers Against Sewage.
They say it highlights the importance of developing tailored waste management strategies that take different regions and communities into account.

Litter pollution is a pressing environmental challenge, yet we still lack a full understanding of where it originates, how it spreads, and which solutions are most effective. To build a clearer picture, our research worked with almost 100 volunteers who tracked waste in their local areas, a demonstration of how communities can provide crucial evidence to drive change. The data revealed how geography and community type shape litter patterns, highlighting the urgent need for tailored waste strategies to be designed and delivered in different areas.

Imogen NapperDr Imogen Napper
Visiting Research Fellow

Imogen led the study with funding from the National Geographical Society

From microplastics in our drinking water to dead whale stomachs filled with discarded plastic bags, the growing amount of litter abandoned in the environment is having a global impact. At the local level, understanding the types of litter in our towns, villages and coasts helps us ramp up efforts to remove this pollution from our ocean and rivers, while also highlighting the importance of investing in means to stop it entering the environment in the first place.

Professor Heather Koldewey
ZSL’s Head of Ocean and FAIRER Conservation 

Surfers Against Sewage has around 700 Plastic Free Communities across the UK, all working on upstream solutions to the plastic pollution crisis. To see nearly 100 ocean activists come together in this huge citizen science project – while cleaning up polluting items from our coastline, green spaces, streets and mountains – is testament to the power of community action and its critical role in research. The project results call for a need for policy change and urgent action to tackle the plastic problem. Decision-makers must implement targeted strategies that consider the differences in location highlighted by this research, and measures that tackle the worst pollutants. Now more than ever, we must see a reduction in plastic production and a concerted effort to create circular systems in the UK, and beyond. With increasing evidence to the presence of micro and nano plastics in the ocean, water, air, soil and even the human body, it's time to turn up the dial and end plastic pollution and its devastating impact.

Rachel Yates
Senior Communities Manager (Plastic Free Communities), Surfers Against Sewage 
litter picking

Comments from participants on the project

I was immediately interested in taking part in this research, as I am passionate about reducing plastic pollution in the local environment. Our group undertakes beach cleaning as a regular monthly activity throughout the year, so taking part in the study was a natural progression. I am excited to hear that the research is now being published and I'm proud to have been a part of it. I am happy to have been a part of something that will add to the information available to decision makers. Plastic pollution is a scourge on our environment and while we have not acted quickly enough to prevent the already devastating effects on ourselves and our precious environment, we can act now to reduce further harmful effects in the future.

Vanessa Riley
Retired teacher and Plastic Free Community lead, Dawlish

I wanted to take part in the research to assist in the understanding of how these pollutants build up in local environments. I was also interested in understanding the impact that a litter pick has on a local area, as in, how long does the impact of tidying up a targeted area last? It's fantastic to see that this citizen science project has become recognized through a scientific journal. I hope the findings can be used to both encourage and direct those organisations, who produce the packaging. As a parent, a local resident, a regular walker and someone who loves having local wildlife flourish around me, reducing plastic pollution at source is really important to how we maintain the beauty we have in our rural areas, and the living standards in our urban areas across the country.

Peter Robinson
College Leader, Worcester
  • The full study – Napper et al: Citizen Science Reveals Litter Trends in the UK: Population Density Effects on Coastal and Inland Regions – is published in Marine Pollution Bulletin, DOI: 10.1016/j.marpolbul.2025.117634.

Read more about related research and activities

More related news

Plastic bottle and other plastic marine litter on a beach
Plastic litter washed up on beach with tree

International Marine Litter Research Unit

Professor Judith Petts and Professor Richard Thompson receive the Queen's Anniversary Price from HRH The Prince of Wales and HRH The Duchess of Cornwall.

Winning the Queen's Anniversary Prize

Close-up wave

Marine Institute

 

Students choose Plymouth for courses related to the sea. Find out why:

Marine Station